[论文解读] How Spontaneous Electrowetting and Surface Charge affect Drop Motion

Chirag Hinduja, Benjamin Leibauer+6 more|arXiv (Cornell University)|Feb 3, 2026

Electrowetting and Microfluidic Technologies被引用 0

一句话总结

简要结论：本文研究在亲水排斥表面上滑动水滴的电荷分离如何诱发自发电润湿和表面电荷效应，从而共同改变接触角，并在后撤线处大多相互抵消。

ABSTRACT

Water drops sliding on hydrophobic surfaces spontaneously separate charges at their rear. It is unclear how this charge separation affects the contact angles of a sliding drop. We slide grounded and insulated drops on hydrophobic surfaces at low capillary numbers (\leq 10^{-4}). We find that drop charge leads to spontaneous electrowetting, which decreases the contact angles. Additionally, the deposited charges lead to a surface charge effect and decrease the contact angle. Both phenomena compensate each other at the receding contact line, resulting in an insignificant change in the receding contact angle of a sliding drop.

研究动机与目标

• Understand how charge separation in sliding drops on hydrophobic surfaces influences contact angles.
• Quantify the effects of spontaneous electrowetting and surface charge on drop motion at low capillary numbers.
• Determine how these opposing effects interact at the receding contact line.

提出的方法

• Slide grounded and insulated water drops on hydrophobic surfaces.
• Operate at low capillary numbers (≤ 10^-4).
• Compare changes in advancing and receding contact angles with and without charge.
• Isolate effects of spontaneous electrowetting from surface charge deposition.

实验结果

研究问题

• RQ1 How does spontaneous electrowetting modify the contact angles of a sliding charged drop?
• RQ2 What is the role of surface-deposited charges in altering drop wetting behavior?
• RQ3 Do spontaneous electrowetting and surface charge effects cancel at the receding contact line for sliding drops?

主要发现

• Drop charge induces spontaneous electrowetting that lowers contact angles.
• Deposited surface charges create a surface charge effect that also lowers contact angles.
• These two effects compensate at the receding contact line, leading to insignificant change in the receding angle.
• The study uses grounded versus insulated drops to distinguish effects at low capillary numbers.